Hydraulic motor



United States Patent [72] Inventor Leonid Mikhailovich Gurevich, 2,910,047 10/1959 Plummer 92/166X ""1 g MOSCOW, U.S.S.R- 2,936,737 5/ 1960 Miller 92/31 [21] Appl. No. 744,133 3,079,896 3/1963 Johnston 92/108X [22] Filed July 11, 1968 3,096,077 7/1963 Forsyth 92/166X Patented Sept. 29, 1970 3,411,409 11/1968 Bunyard 92/l66X Primary Examiner-Martin Pv Schwadron BRA uc MOTOR Assistant Examiner-Les li e J. Payne [.54] ga Drawing Fig Attorney- Waters, Rodm, Schwartz and Nissen [52] US. Cl 92/31,

92/33, 92/50, 92/69, 92/75,92/1l l, 74/84.4 [5 1] Int. Cl F0lb 3/06, ABSTRACT; A hydraulic motor is provided in which Folb reciprocating motion of a pair of pistons is converted into an oISearch l 32, intermittent angular motion of a driving member mean of ,1 -l 2/ a kinematic screw-and-nut assembly, The pistons are em- 5 110, 1 I3, I ll ployed as a nut, and the shaft of the hydraulic motor, as a screw. inside the shaft there are provided isolated channels for [56] References cited supplying working fluid into the working chambers of the UMTED STATES PATENTS cylinder and for discharge therefrom. The pistons and cylinder 1,056,616 3/1913 Wright et a1. 92/33 are interconnected by bars for transmitting torque l,95l,030 3/1934 Nardone 92/166 therebetween and in the bars are channels intercommunicat- 2,199,328 4/1940 Baer et al 92/31X ing corresponding working chambers of the cylinder.

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HYDRAULIC MOTOR This invention relates to hydraulic drive units and more specifically it relates to intermittent-action piston-screw hydraulic motors.

Known in the art are hydraulic motors wherein the reciprocating motion of the piston is converted into intermittent angular motion of a driving member by a kinematic screw-and-nut pair (see, for example, Hydraulic Crane 4030. Frection. Operation and Maintenance Manual," Lvov.

l96l, p. 6. Drwg 2).

ln the known hydraulic motors, the working medium is fed in directly through the cylinder body which actually excludes the possibility of using both the shaft and cylinder as a driving member and, consequently, the possibility of intermittent alternating angular motion of the cylinder and shaft in one and the same direction.

An object of the present invention resides in providing a hydraulic motor wherein both the shaft and cylinder can be used as driving members whose operating sequence is determined by the order in which the connected mechanisms are locked and released.

In compliance with this object there is provided a hydraulic motor wherein the reciprocating motion of at least one piston of the hydraulic motor is converted into intermittent angular motion of the driving member by means of the kinematic screw-and-nut pair. According to the invention, the shaft installed in the hydraulic cylinder and provided with a guiding thread of the kinematic pair has inside isolated channels, connecting the working chambers of the cylinder with the main pipe lines for the purpose of ensuring the possibility of employment of both the shaft and cylinder as driving members.

It is practicable to make the channels, communicating the like chambers of the cylinder, in bars the torque being imparted to said bars from the pistons.

It is also practicable to fasten the bars in the cylinder with the aid of elastic bushings.

Given below is a description of an embodiment of this invention with reference to the appended drawing which illustrates a longitudinal section of the hydraulic motor according to the invention.

Accommodated inside a cylinder 1 closed at both ends with plugs 2 is a shaft 3 provided with two sections of oppositely directed non-self-locking threads on which pistons 4 are mounted.

The shaft 3 carrying the pistons 4 forms the kinematic screw-and-nut pair.

The pistons 4 divide the cylinder 1 into three working cham bers: two end chambers 5, 6 and a middle chamber 7.

The two end chambers 5 and 6 operate in the same manner and simultaneously either as pressure or discharge or chambers.

The pistons 4 are provided with peripheral holes, through which pass bars 8 fastened in the plugs 2 of the cylinder 1 by means of elastic bushings 9. The torque is imparted to these bars from the piston 4.

The bars 8 have channels 10 which intercommunicate the end chambers 5 and 6 of the cylinder 1.

Inside the shaft 3 are isolated channels ll and 12, each communicating with a corresponding main pipe line (not shown in the drawing). The channel 11 communicates with the working chamber 5 and the channel 12 with the working chamber 7.

The working chamber 5 communicates with the working chamber 6 through the channels 10 in the bars 8.

The hydraulic motor operates as follows.

The working medium is delivered under pressure through the channel 1] into the end chamber 5 wherefrom it is bypassed through the channels 10 in the bars 8 into the opposite end chamber 6. The pistons 4 are moved by the pressure of the working medium and displace the fluid from the middle chamber 7 into the discharge line through the channel 12.

When the working medium is delivered through the channel 12, the operating process described therein is reversed and the fluid is discharged through the channel 11.

The kinematic screw-and-nut pair, wherein the role of the nut is fulfilled by the piston 4 and that of the screw is fulfilled by the shaft 3, converts the reciprocating motion of the pistons 4 into an intermittent angular motion of the driving member. When the cylinder 1 is locked, the shaft 3 is a driving member and conversely, with the shaft 3 locked, the cylinder 1 is a driving member.

During the rotation of the shaft 3, the bars 8 are imparted with torque reaction and transmit it through the elastic bushings 9 to the locked cylinder 1. If the shaft 3 is locked, these bars transmit the torque from the pistons 4 to the cylinder 1.

This allows both the cylinder 1 and shaft 3 to be used as driving members whose operating sequence is determined by the order of locking and releasing of the mechanisms connected to them, For example, when these mechanisms are locked alternatively after each working stroke of the pistons 4, this causes intermittent alternating angular motion of the driving members, that is the shaft 3 and cylinder 1, in one and the same direction.

I claim:

1. A hydraulic motor comprising: a cylinder; at least one piston located within said cylinder and having a threaded inside surface; said piston defining working chambers in said cylinder; a shaft mounted in said cylinder and including an external thread on which said piston is threadably mounted for travel therealohg, said shaft being provided with isolated axial channels at opposite ends thereof respectively for supplying working fluid to said working chambers of said cylinder and for discharge therefrom; and means interconnecting said piston and cylinder for transmitting torque therebetween.

2. A motor as claimed in claim 1, wherein two of said pistons are mounted on said shaft and define a middle working chamber and two end chambers, said means for transmitting torque between the pistons and cylinders having channels providing intercommunication between the end chambers, said isolated channels in said shaft being two in number and respectively in communication with the middle chamber and said end chambers.

3. A motor as claimed in claim 1, wherein said means interconnecting the piston and cylinder comprises bars extending longitudinally through said pistons and engaging said cylinder, said channels which provide intercommunication between the end channels being disposed in said bars.

4. A motor as claimed in claim 3, wherein said means interconnecting the piston and cylinder further comprises elastic bushings in said cylinders absorbing axial and transverse forces from the torque transmitted between said pistons and cylinder.

5. A motor as claimed in claim 4, wherein said bushings encircle the bars at the ends thereof.

6. A motor as claimed in claim 2, wherein the threads on the inside surfaces of said pistons are of opposite hand and the external thread on the shaft includes two portions of opposite hand respectively engaged with said pistons. 

